A blog by Catharine Ellis

Month: October 2018

I first met Sarah Bellos of Stony Creek Colors in 2016 when she spoke at the Growing Color Symposium at the NC Arboretum in Asheville. She presented her vision for growing and extracting indigo in Tennessee. Her goal was to introduce natural indigo to the denim industry, which is currently a huge consumer of synthetic indigo (a serious source of environmental pollution). She was partnering with Tennessee farmers who had previously grown tobacco and planned to process indigo dye locally.

Air drying of traditional burley tobacco in TNSome Tennessee grown tobacco is cured by smoking with wood fire

I must admit that I was somewhat skeptical. The project seemed too big and too optimistic. I didn’t know anyone who had successfully grown indigo dye plants on the scale that she described.Most dye plants are grown for commercial purposes in India or South America, where the price of labor is far less. Indigo was grown in the Southeast coastal regions of South Carolina and Georgia in the 17th and 18th centuries but, to my knowledge, has not been grown commercially in North America since that time.

On a recent visit to Stony Creek near Nashville, TN I was very pleasantly surprised and now believe that they are truly on the way to something successful and very much needed. I’d like to tell you why I believe this.

The first place visited was the “test farm”.I had envisioned a small plot of Persicaria tinctoria but was amazed to find that the test farm was a densely planted, multiple acre farm tract where several strains of Persicaria tinctoria are growing next to the tropical varieties of indigo(Indigofera suffruticosa and Indigofera tinctoria).

Tropical indigo plants (Indigofera suffruticosa), harvested and continuing to grow in foreground, not yet harvested in backgroundSarah in the test field, where several varieties of indigo are grownPersicaria tinctoria, in bloom

Why grow so many different types of plants? Sarah and her staff are constantly asking questions and testing: Which varieties can be sown directly in the ground? Which need to be started in the greenhouse? Some strains bloom more readily than others (great for seed production but not so good for indigo production). Which plants can be dried for future extraction? What is the indigotin content vs. the biomass of the plants? Which can be harvested most efficiently?

I believe that the Stony Creek team is concluding that there is wisdom in growing more than one variety of indigo.The farmers are currently growing many acres of indigo for pigment extraction. All farms are within a reasonable drive to the factory, as it is necessary to process the indigo leaves quickly.

The next stop was Stony Creek’s lab.Walking in the door I saw that the dye chemist, Summer Arrowood, was pulling leaves from Persicaria tinctoria stems that had been harvested earlier that morning. She was weighing those leaves and recording the leaf-to-stem ratio. Next, individual bags of leaves (from very specific plants in very carefully identified locations at the test farm) were processed to extract the indigo pigment. I sensed that this was part of each day’s work at the lab. The leaves were soaked in hot water, the liquid was pumped into vessels for aeration, the paste was allowed to settle and then filtered. Several hours later, each batch of leaves had produced a small amount of indigo pigment. These were tested, labelled and stored for future reference. They report that their indigo contains 25-35% indigotin which is a very concentrated output.

Vessels for test extractions of pigment. Sarah is holding the piping used for introducing oxygen into the indigo extraction in order to precipitate the pigment.Filtering of test pigmentPigment extracted from test extractionsEach sample batch of pigment is carefully labeled for reference

Stony Creek is experimenting with extraction from dried plant material in order to extend the production season.

The production factory is located in a county-owned, former tobacco factory and leased by Stony Creek.Here, 20,000 pounds of indigo plant material can be processed in a single batch. The factory is set up with modern equipment, carefully laid out, and efficient. Stony Creek precipitates indigo pigment without the use of lime (calcium hydroxide). When too much lime is used during the process, it will remain in the indigo pigment and skew the weight of anyavailable indigotin. The extraction without lime is one of the reasons the pigment has such high levels of indigotin. The pigment paste is carefully filtered using processes that Stony Creek has developed specifically for indigo.

Truck trailers used for indigo harvest and initial steeping of plants.Water that has been collected from the root and heated in solar tanks is used for extracting the indigo.Stainless tanks are used for aerating the indigo. Stony Creek has recently installed two additional tanks.Plastic tanks are used for settling of the indigo paste.All indigo paste settles to the very bottom of the tanks. The remainder is waste water, that is properly neutralized before discarding.

How has Stony Creek come this far so quickly? Sarah Bellos has an academic background and experience in natural resources management and sustainable agriculture. She is a self-taught natural dyer; she and her sisters operated a dye business for several years under the name Artisan Natural Dyeworks. Stony Creek employs skilled and smart people, who know chemistry, plants, agriculture, and manufacturing. The farmers, who grow the indigo, are benefiting from a cash crop that has the potential to replace the tobacco that grew here for so long. Stony Creek is currently selling indigo paste to denim producers and they are able to test/replicate the warp dyeing process used by the denim industry in their lab. Sarah had a vision to produce natural indigo and they are making it a reality.

This chart says it all!

At a time when some of us are unsure if we are purchasing natural indigo or synthetic indigo (or a mix of both) Stony Creek is a beacon of light. I have used their indigo and it is excellent. Of course I will purchase my indigo from them! I will encourage other dyers to do the same.

Stony Creek is NOT yet set up for visitors. Right now, they need to focus on the work at hand and continue to develop their current products: indigo, black walnut paste extract (that really works!), and a madder extract paste (currently from Rubia tinctorium roots grown in India until their own roots are ready for harvest).

After this year’s indigo harvest they plan to move the lab to the factory location and at some time in the future will be able to offer workshops onsite. I hope that you will consider helping to grow this promising endeavor by trying out their excellent indigo, and other extracts available for order online at their website. Other dye suppliers are also beginning to carry and sell Stony Creek Indigo.

The day we visited the factory, there was no indigo being processed. It had rained the day before and the indigo plants cannot be harvested when wet; this whole process is tied closely to the land. Before we left in the afternoon, the truck and trailer had left for the fields, ready to be loaded with indigo plants early the next morning.

Yesterday I received a phone call from Schiffer Publications – the publisher of Joy’s and my upcoming natural dye book.

I am sorry to report that the release date, originally projected for the end of October, has been delayed until late January.

Why the delay?

Schiffer is taking great pains to be sure that all color reproduction is exact and precise. The book is illustrated with photos of actual samples from my dye tests. Our goal was to share some of the hundreds of samples that I have done, comparing the use of different mordants, tannins, dye treatments, times in the dyebath, etc. Many of the variations are subtle – but the differences are important.

Careful color adjustments have been made to the digital images in Art & Science of Natural Dye to ensure that the dye colorsreproduce as accurately as possible throughthe print process. Color proofs arereviewed and compared to the actual dye samples as part of this process.

Yes, it will be delayed, but the color will be the best possible printed reproduction and I’m very happy about that. It’s good to be working with a publisher that really cares about these “small” details – they are really not small at all. Below is just a small hint of what will be included.

black walnut on wool

cochineal variations on silk

pomegranate dye variations

comparison of mordants on cellulose

printing of ferrous acetate with different tannins and dye

cross dyeing of wool and cotton

use of iron post mordant

various tannins with mordants and dye

indigo print

indigo discharge

I know that many of you have pre-ordered the book and are anxiously awaiting it. Joy and I appreciate the vote of confidence and are sorry for the delay.

I can suggest a great thing to do while you’re waiting:

Yesterday, on a long drive back home from New England, I finally had the chance to listen to a lecture given by Michel Garcia and available as a Maiwa Podcast. It’s title is Field Notes in the Color Garden, parts 1 & 2. It’s a long, wonderful, rambling lecture that Michel gave in 2015 and Maiwa uploaded as a podcast this year.It has given me much to think about in regards to dye plants, resource books, investigation, and the human scale of natural dye.

And keep dyeing!

It’s still less than a year since Joy and I turned in the manuscript and images to the publisher. My learning has not stopped and once the book is released, I look forward to sharing some of the things I’ve continued to work on and learn about since we sent the manuscript away.“Stay tuned”.

I have always enjoyed how the goldenrod grows and blooms alongside the purple asters – a beautiful combination of complimentary colors.Goldenrod (Solidago sp.) is a member of the aster family. There are many solidago species native to North America, and they can also be found in other parts of the world.

Goldenrod flowers, gathered in western North Carolina

Goldenrod and New England Asters, photo from Denver Botanical Gardens

Goldenrod and thistles, Newfoundland, CA

Is goldenrod a good source of dye? Yes, but with reservations.

Though it is not one of the “classical” dyes, and it’s lightfastness does not match that of weld, it was used as a locally available dye in North American and Europe. Dominique Cardon (Natural Dyes: Sources, Tradition, Technology, and Science) writes about goldenrod’s historical use, along with weld and Persian berries, to dye the yellow hats the Jews were required to wear in the south of France in the 13th century.

I’ve always readthat goldenrod does NOT dry well for future use – so I never tried to dry it. I can accept the fact that some dyes deteriorate in the drying process. Black walnut hulls are a good example.

A couple years ago I was teaching a class here in Asheville, NC on dyes that could be sourced from the local food co-op. I used dried goldenrod plant material, as it is used medicinally. It resulted in very good color. So I began to wonder….. CAN A GOOD DYE BE OBTAINED FROM DRIED GOLDENROD?

It’s one thing to read a statement about a plant – it’s another thing to know and understand that statement. Ihad never tried to dry goldenrod. This year I finally got around to doing my own testing.

I gathered fresh goldenrod, and used that to dye aluminum mordanted wool, silk, and cotton. There are many yellow dyes in goldenrod and they may include quercitron, isoquercitron, kaempferol, astragalin, isorhamnetin. Since the dyes in goldenrod are primarily flavonols, a mordant is required.

I dried goldenrod from that same harvest. Plants were hung upside down in a dry space with plenty of air flow. Only the flowering heads were used as a source of dye. I was able to accurately determine the weight of the plant before and after drying. 300 grams of fresh goldenrod flowers resulted in 100 grams of dry flowers.

100 grams of dried flowers (left) and 300 grams fresh flowers (right)

I dyed with fresh goldenrod at 300% w.o.f, while the dried was used at 100% w.o.f. Because I knew the weight before and after drying, I was confident that I was using the same amount of dye, whether it was fresh or dry plant material.

The results: The dyes seem not to have suffered from the drying process. Careful drying is likely a key element. So yes, I will dry some goldenrod and I will complete lightfastness tests on all three fibers. The goldenrod will not replace the weld that I grow and dry each year, Weld will always be my primary yellow dye as that has proven to be the best, and most lightfast yellow dye. But it is good to know a bit more about the dyes from plants available in my neighborhood.

Thus far I have used only the flower heads for dyeing. Maybe next year I’ll experiment with the stems and leaves from the entire plant.